1. Field of the Invention
The present invention relates generally to keyboards and more particularly pertains to miniature hand held electronic keyboard assemblies.
2. Description of the Prior Art
Electronic keyboards in their basic form include a plurality of position fixed depressible keys each associated with a specific character or function. Such keyboards are employed in a wide range of equipment such as typewriters and calculators and range in size from, for example, large computer keyboards to small credit card size keyboards. Where the keyboard is intended to be easily operated as in a computer or typewriter, then the keys and corresponding keyboards must be of appreciable size in order to accommodate a human finger. When, however, a small size keyboard is desired, consideration must be given to maintaining adequate key size for permitting comfortable key manipulation.
Presently available miniature keyboards with position fixed depressible keybuttons have extremely small and closely spaced keybuttons. These miniature keyboards are difficult to hand operate due to the size of the human finger and such hand operation may result in the unintentional simultaneous activation of several keybuttons or activation of an incorrect keybutton.
A number of techniques have recently been developed to reduce the number of required keybuttons so that for a given size keyboard, a larger keybutton may be used. Thus, U.S. Pat. No. 3,428,747 discloses a technique for achieving a substantial reduction in the total number of fixed operable keys by combining the characters and functions of various keys. Another technique, as shown in U.S. Pat. No. 4,324,976, includes a hand held fixed key calculator which includes first and second keyboards on the front and rear faces of the device, thus reducing the number of required keybuttons on one side of the calculator. Still further, U.S. Pat. No. 4,520,240 discloses a four way integral slide switch for control of cursor positioning reducing the number of switches and the size of the keyboard. The electronic one hand operable keyboard shown in U.S. Pat. No. 5,087,910 employs fixed switches each capable of assuming a plurality of states in response to finger activation. Each switch or key can be used to activate a plurality of characters or functions to thereby reduce the number of keys or switches required. U.S. Pat. No. 4,458,238 includes a device having a handle which supports a display board. The handle includes at least four fixed switches for selecting sequentially illuminated characters and functions illustrated on the board for data entry storage. Thus a reduced number of switches or keys may be achieved.
The keyboard assembly for selecting characters to be recorded disclosed in U.S. Pat. No. 4,722,621 includes a substrate which carries an array of displayed characters. Movement of a character selection device along two axes of the array serves to control the recording of the character selected. The physical movement of the selection device by the operator positions the print element for recording and generates analog signals identifying the selected character. The analog data is then converted into digital data which is processed and stored.